The present invention relates to a solution feeding apparatus. More particularly, the invention relates to an apparatus that may be used, for example, as a replenishing apparatus to replenish a processing solution for processing a silver halide photographic material using an automatic developing apparatus.
Typical examples of methods of processing a silver halide photographic material after exposure of the photographic material to a light image include those which are employed for processing a monochrome photograph and comprised of such processes as developing, fixing, water washing and drying; those employed for processing a color negative film and comprised of such processes as color developing, bleaching, fixing, water washing, stabilizing and drying; and those employed for processing a color paper and comprised of such processes as color developing, bleaching fixing, water washing, stabilizing and drying. These processes are usually conducted with an automatic developing apparatus by using respective processing solutions. As use of an automatic developing apparatus is becoming more commonplace, using a rinse or other substitute solution in lieu of water washing is on the increase. Compositions of these developing solutions and fixing solutions change as a result of processing a silver halide photographic material. In addition, the elapse of time, developing solutions and fixing solutions suffer from decrease in their effectiveness due to air oxidation. In order to prevent these problems and maintain the processing solutions sufficiently effective during continuous processing using an automatic developing apparatus, it is common practice to replenish each respective processing solution with a replenishment solution having a composition either the same as or similar to that of the processing solution.
Each solution for processing a silver halide photographic material is usually supplied in the form of a condensed liquid and requires dilution with water to a given concentration before actually used. In this case, the dilution has to be done precisely; a silver halide photographic material processed with an inaccurately dilutes processing solution may result in a finished photograph having a considerably poor quality.
Some kind of solution, such as a color developing solution or a bleaching fixing solution, is supplied in a plurality of solution parts in order to increase the preservability not desirable to contact therewith. When actually used, such a solution has to be prepared by mixing the concentrated stock solutions, each of which usually consists of two to four solution parts, such as mistaking a solution part for that of another processing solution, often happen. It is not uncommon that such a mistake seriously and irreparably impairs the quality of the finished photograph.
As described above, preparation of processing solutions imposes a heavy burden on the operator, because it is not only complicated but also requires precision. Furthermore, it often happens that a condensed solution or a prepared solution spill or spatter onto nearby objects, such as a human body, clothes or furniture and equipment, sometimes contaminating or otherwise damaging the objects. In order to prevent these problems, it has been practiced to supply each processing solution in the form of a ready-to-use solution, with the conditions of the solution adjusted beforehand. Nevertheless, supplying a solution in the form of a concentrated stock solution still has advantages in that is occupies less space for distribution or storage and that it has superior stability in preservation.
When solutions that have been prepared as above are used as replenishment solutions, they are usually stored in separate, respective replenisher tanks, from which a necessary quantity of each respective replenishment solution for the current stage of processing a silver halide photographic material is fed into a solution tank in the automatic developing apparatus with a pump or by other appropriate means. At that time, as the replenishment solutions in the replenisher tanks are stored in such a state as to be exposed to the air, they present the possibility of becoming concentrate due to evaporation of moisture as well as quality deterioration resulting from air oxidation. Should a processing solution be replenished with a replenishment solution that has thus become deteriorated or changed in quality, effectiveness of the processing solution decreases, resulting in poor image quality of the finished photograph.
Examples of means to prevent such a deterioration include a method that calls for disposing a floating lid or a floating ball in a replenisher tank to cover the surface of replenishment solution and thus reduce the area of the surface of the replenishment solution in contact with the air. However such a method has not yet succeeded in completely isolating a solution from air. In view of preservation of the environment and natural resources, the quantity of replenishment solution used for processing a silver halide photographic material is on the decrease in recent years. Therefore, if a replenishment solution is prepared in the same amount as before, it is stored in a replenisher tank for a longer period of time until it is used up and more likely to change in quality. Furthermore, reduction in the amount replenished present a problem in that even a minimal change in quality of a replenishment solution would make it difficult to maintain the constant effectiveness of the processing solution in an automatic developing apparatus and influence the quality of the finished photographs.
In order to prevent these problems, it is often practiced in recent years to feed a given quantity of water from a diluent water storage tank into a processing solution tank in an automatic developing apparatus simultaneously with drawing a formulated concentrate of processing solution out of its container and directly feeding it into the processing solution tank. Such a method has a benefit in that it eliminates the necessity of preparation of replenishment solutions. In many cases, the above method calls for a flow sensor installed in a container and acting as a solution depletion sensor to detect the solution in the container has been used. Accordingly, such a method typically calls for using a stock solution container made of a polyethylene bottle or other hard-type bottle that will be free from the problem of becoming deformed when the content is reduced. When such a bottle is used, the quantity of air inside the container increases with the decrease of the stock solution in the container. Therefore, the method is not capable of solving the problem of the concentrated stock solution deteriorating due to contact with the air. The method presents another problem in that it is difficult to form a structure where the solution depletion sensor is prevented from registering detection by mistake when there still remains the solution in the container. In other words, it is difficult to use up the solution in the container and often contaminate a human body, clothes or other objects in the environment at the time of disposal of the used container.
In order to solve the above problems, the applicant of the present invention had previously offered solution feeding methods and apparatuses used for said methods, which are disclosed in Japanese Patent Public Disclosure Nos. 52553-1999 and 102056-1999. The problem of a stock solutions deteriorating due to exposure to air can be solved by any one of the above inventions by using a container made of a deformable material as a container to be filled with a concentrated stock solution and inserting a tube or other appropriate member into the stick solution container so as to suction the solution out of the container while maintaining the container airtight. Although the container is flexible, each one of the above inventions is capable of precisely detecting that the solution in the container has been used up.
The inventions mentioned above are highly effective in the ability of preserving the stability of solutions and being convenient to prepare solutions. Each one of the above inventions is the optimal system to be used in normal, small-to-medium-sized developing laboratory. However, when used in a large-scale laboratory where processing solutions are consumed in great quantities, there is a demand for modification in certain points, which are described hereunder. As each one of the above inventions is prone to malfunction in case a great quantity of air enters a solution channel, it is necessary to reduce to an absolute minimum the quantity of air that may possibly enter a solution channel. Therefore, the most desirable method of connecting a solution container to an apparatus has heretofore been what is commonly called a penetration method that calls for sticking a tube directly into a container to connect the container to the apparatus and drawing the solution up out of the container. When a penetration method such as above is employed, it is easy to limit the quantity of air that might enter the container to a minimum. On the other hand, it is necessary to use a container suitable for a penetration method, i.e., a container made of such a material as to prevent the solution in the container from leaking from the position where a tube is stuck into the container. As a problem concerning the strength of such a material makes it impossible to produce containers having a large capacity and, at the same time, suitable for a penetration method, employing a penetration method necessitate the use of a relatively small container. This imposes a considerable burden particularly upon operators working at major developing laboratories which handle a great quantity of processing each day, each time a container solution in the container is quickly used up, and it is therefore necessary to replace containers many times a day.
For the reason describe above, it is a common practice at a major developing laboratory or the like to connect a large container to an apparatus by a method other than a penetration method. However, other methods, too, present various problems. For example in case of a method that calls for connecting a container to a solution feeding apparatus by removing a cap of the container to a solution feeding apparatus by removing a cap of the container and sealing the container with a plug that is connected to a tube, it is difficult to connect the container while limiting the air entering the container to a minimal quantity, because the air can easily enter the container when the cap is removed. Furthermore, should the feeding of the solution be initiated without thoroughly removing the air from the container, a large amount of gas inevitably flows into the solution channel, often impairing accurate solution-feeding or resulting in premature activation of a sensor adapted to detect that the container is empty.
There also is a method which calls for a plurality of small containers connected to an apparatus by using a penetration method. This method, however, is prone to present a problem of occupying an excessively large space, because it requires numerous containers in order to reduce the frequency of replacing containers. Furthermore, the larger the number of containers connected to an apparatus, the greater the total quantity of gas entering the solutions channels, even if the quantity of gas entering each container is minimal. Therefore, the number of containers used in actual practice is limited.
For the reasons stated as above, there is a demand for a solution feeding apparatus that is capable of feeding solution from its container until the container is completely empty while maintaining precise feeding accuracy, said apparatus having the effect described above regardless of whether entry of a large quantity of air into a solution channel is unavoidable, which tends to happen when a container is connected to an apparatus by using a method other than a penetration method or when a plurality of small containers are connected to an apparatus.
In order to solve the above problems, a feature of the present invention lies in providing a solution feeding apparatus which calls for connecting a solution-feeding pump through a tube to a container that contains a solution and is capable of changing its shape in accordance with the amount of its content, wherein a gas increase prevention mechanism is provided in a solution channel.
According to an embodiment of the present invention, the invention relates to a solution feeding apparatus which calls for connecting a solution-feeding pump via a tube to a container that hermetically contains a solution and is capable of changing its shape in accordance with the amount of its content, wherein a gas increase prevention mechanism is provided in a solution channel. With the configuration as above, an accurate solution-feeding rate is maintained even if a great amount of gas enters the solution channel, such as intrusion of a great amount of gas being unavoidable when, for example, any method other than penetration method is employed to set the container or when a plurality of containers are connected to the apparatus. Furthermore, the invention does not impose limitations in types of containers that can be used for the inventions and permits use of a large-capacity container, which is unsuitable for a penetration method or use of a plurality of container. Therefore, the invention enables the substantial reduction of the labor required by replacing a container or containers.
According to a further embodiment of the present invention, an airtight channel between a container and the solution-feeding pump is provided with a gas-liquid separation tank adapted to separate gas from a solution, and the gas increase prevention mechanism is comprised of a gas detection sensor and an air pump, the gas detection sensor disposed in said gas-liquid separation tank, and the air pump being so adapted as to function in sync with the gas detection sensor to discharge gas out of the gas-liquid separation tank. As the invention enables the complete separation of gas from solution in the solution channel and the discharge of the gas out of the solution channel, the invention prevents the gas from entering the solution-feeding pump and is therefore capable of more reliably maintaining a precise solution-feeding rate.
As a solution-feeding stopping device may be disposed between the container and the gas-liquid separation tank, the invention is capable of preventing solution from continuously flowing from the container into the gas-liquid separation tank by siphonage even after the solution-feeding pump is halted.
As the airtight channel between a container and the solution-feeding pump is provided with a solution depletion sensor adapted to detect that the container has become empty of solution, the invention is capable of feeding solution from its container while maintaining precise feeding rate to the end of the feeding process. In addition, as it is capable of accurately detecting that the container has become empty of solution, the invention is capable of halting feeding of the solution at the appropriate moment without the possibility of gas entering the solution-feeding pump.
As a gas discharge tube connected to the air pump may be provided with one or more check valves, the invention enables the complete discharge of gas and is free from the problem of intrusion of outside air into the airtight channel. Therefore, the invention is capable of preventing malfunction of the gas detection sensor or the solution depletion sensor.
As solution depletion sensor may be disposed in the gas-liquid separation tank, the invention eliminated the possibility of malfunction of the solution depletion sensor, which might otherwise be caused by a minimal amount of gas in the airtight channel. Therefore, the invention enables the more accurate detection of depletion of a container and more reliable prevention of intrusion of gas into the solution-feeding pump.
As the gas detection sensor disposed in the gas-liquid separation tank may also be located higher than the solution depletion sensor, the invention eliminates the possibility of malfunction of the solution depletion sensor and enables the complete consumption of solution in a container.
As the invention according to an embodiment calls for controlling the solution-feeding pump based on detection of reduction of the pressure in the solution channel by the solution depletion senor, the invention enables the complete consumption of solution in a container and is capable of halting feeding of the solution at the appropriate moment without the possibility of gas entering the solution-feeding pump.
As the invention may include a tube which can be connected to a plurality of containers, it is possible to use the apparatus with a plurality of containers connected thereto. Therefore, the invention enables the substantial reduction of the labor required by replacing containers evening case the apparatus is used for feeding a great quantity of solution.
According to another embodiment of the present invention, the invention relates to a method of feeding a solution by connecting a solution-feeding pump via a tube to a container which hermetically contains a solution and is capable of changing its shape in accordance with the amount of its content, said method calling for separating gas from the solution by means of a gas-liquid separation tank that is a part of an airtight channel extending from the container to the pump; and discharging the gas out of the solution channel by means of a gas increase prevention mechanism so that the gas in said gas-liquid separation tank is maintained at a constant quantity. Therefore, complete separation of gas from the solution in the solution channel and discharge of the gas completely out of the system can be conducted so that a precise solution-feeding rate is maintained even if a great amount of gas enters the solution channel, such an intrusion of great amount of gas being unavoidable when, for example, any method other than a penetration method is employed to set the container or when a plurality of containers are connected to the apparatus. Furthermore, the invention does not impose limitations in types of containers that can be used for the inventions and permits use of a large-capacity container which is unsuitable for a penetration method or use of a plurality of container. Therefore, the invention enables the substantial reduction of the labor required by replacing a container or containers.
According to a further aspect of the present invention, connection or removal of a container and a solution feeding apparatus to or from each other can be conducted with extreme case by using a simple mechanism. The invention has another benefit in that it enables the smooth, easy replacement of numeral containers with a minimal amount of force by using leverage. These and other aspects and advantages of the invention will become apparent upon a reading of the detailed description in conjunction with the drawings.